Smoke detector



FIG. 1 is a perspective view of a smoke detector showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevational view thereof with the opposite side a mirror image of FIG. 4; and

FIG. 5 is a left end elevational view thereof with the opposite end a mirror image of FIG. 5. 

The ornamental design for a smoke detector, as shown and described. 